Fighting for survival, the gentleman's club for spies and the SAS

Hidden in a quiet London side street with no nameplate on the door is one of Britain's most exclusive and shadowy private clubs.

Membership of the Knightsbridge-based Special Forces Club is strictly limited to Britain's current and former military and intelligence elite.

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In debt: The Special Forces Club and, inset, Agent 'Madeleine'

But the establishment's usually quietly conspiratorial atmosphere is now charged with bitter unrest as it faces spiralling debts, falling membership and fears for its survival.

Founded by the Second World War resistance organisers, the Special Operations Executive (SOE), in 1946, the club - motto 'Spirit Of Resistance' - is a second home for ageing secret agents, veterans of the SAS, other special forces, and MI5, MI6 and CIA officers.

Located in an unremarkable Victorian terrace in Herbert Crescent, behind Harrods department store, the club's fine dining room and bar are where the conspirators behind the alleged plot to overthrow Labour Prime Minister Harold Wilson met to plan the putsch.

It was here, too, that Britain's most important wartime agent 'Garbo' - who helped mislead the Germans about the location of the D-Day landing -came in from the cold, calling in for tea with his British handlers.

Among the portraits lining the stairs is one of the beautiful Madeleine, SOE spy Noor Inayat Khan, who was sent to Dachau concentration camp and shot.

But the club's existence is now threatened by extraordinary claims, including one that its chairman, ex-Royal Marine and Special Boat Service hero Major 'Ram' Seeger's, election was illegal and allegations of fraud.

The membership is divided over whether the club should take on charity status - a move which would curb its debts but disbar the descendants of SOE war heroes and wealthy private security firms.

Last month Major Seeger wrote to 2,500 members revealing losses running at £8,000 a month and an annual deficit of £138,000. He said: 'The club is depleting its reserves, has unsatisfactory working practices and there are strongly held differing views on the best way forward.

'Once it was realised last year that we were not going to break even, it was clear something much more radical had to be done. An independent auditor examined the financial controls and management system and came up with some fairly damning comments.'

Maj Seeger said the club management had to be restructured 'since without sound management the club has no future'. He revealed the club's management committee had been 'divided with no realistic prospect of agreement' which had led to a series of resignations - and that membership was at 'its lowest level', nearly 900 below what was needed to break even.

Maj Seeger was also forced to dismiss claims of theft and fraud involving staff and that his own election had been illegal. He said an internal audit had 'found no evidence of malfeasance'.

He told The Mail on Sunday: 'All these difficulties can be overcome and we are confident the club will continue to flourish.'